1. Field of the Invention
The present invention relates to a broadcast receiving apparatus that is capable of receiving both of a digital broadcast and an analog broadcast.
2. Description of the Related Art
Conventionally, with respect to a broadcast receiving apparatus that receives an analog broadcast, there has been an apparatus that is provided with a function to automatically set an internal clock thereof, by obtaining time information from a broadcast signal. For example, in a case where it is known that a television broadcast of a predetermined broadcast station gives time signal at a predetermined time, there is an apparatus that extracts an audio signal of the time signal and adjusts an internal clock thereof in accordance with the audio signal. Alternatively, in a case where there is a broadcast station that transmits time data to an extended data service (XDS) signal, the XDS signal being inserted in an analog television broadcast signal, there is an apparatus that extracts the time data of the XDS signal and sets an internal clock thereof in accordance with the extracted time data.
Further, with respect to a digital broadcast of recent years, since time information is inserted in a streaming data which transmits image data and audio data, internal clock can be set in accordance with this time information.
In Japanese Patent Application Publication (Laid-open) No. 2005-127921 and Japanese Patent Application Publication (Laid-open) No. 2005-233750, a technique to set an internal clock in accordance with a digital broadcast signal is disclosed. In Japanese Patent Application Publication (Laid-open) Tokukaihei 07-307931 and Japanese Patent Application Publication (Laid-open) No. 2004-096368, a technique to set an internal clock in accordance with an analog broadcast signal is disclosed.
With respect to the digital broadcast, since time information is always transmitted, there is an advantage that time setting can be conducted quickly. However, since time information is inserted by a producing station of a broadcast program when the streaming data is generated, it is difficult to alter only that portion afterwards. Therefore, in a case where a local station transmits a digital broadcast of a main station with intermediation, or in a case where the broadcast program is re-broadcasted at a different time, there is a problem that time information in the broadcast signal is shifted from the actual time, or is completely different from the actual time.
On the other hand, with respect to the analog broadcast, there is an advantage in that since the time data is structured to be inserted in between the broadcast signals, each of the stations can insert correct time information. However, since time information is inserted in between the signals that are limited, time information cannot be transmitted frequently, and thus time setting requires time.
Accordingly, a channel that is suitable to conduct time setting differs depending on the region where the apparatus is used. In some regions, the suitable channel is a predetermined channel of the digital broadcast, and in other regions, the suitable channel is a predetermined channel of the analog broadcast.